1. Field of the Invention
This application is related to a U.S. patent applications Ser. No. 11/448,314, entitled “IMAGE SENSOR CHIP PACKAGE”, by Steven Webster et al. Such application has the same assignee as the instant application and has been concurrently filed herewith. The disclosure of the above identified applications is incorporated herein by reference.
2. Discussion of the Related Art
Image sensors are widely used in digital camera modules in order to convert the optical image data of an object into electrical signals. In order to protect the image sensor from contamination or pollution (i.e. from dust or water vapor), the image sensor is generally sealed in a structural package.
A typical image sensor chip package (not labeled) is illustrated in FIG. 1. The image sensor chip package is constructed to include a plurality of conductors 130, a base 146, a chip 152 and a cover 158. The base 146 includes a bottom portion 1462 and four sidewalls 1464. The bottom portion 1462 and the sidewalls 1464 cooperatively form a space 150. Each conductor 130 includes a first conductive portion 132, a second conductive portion 134 and a third conductive portion 136. Each of the first and second conductive portions 132, 134 is mounted on one side of the bottom portion 1462 separately. The third conductive portion 136 runs through the bottom portion 1462 so as to connect the first and second conductive portions 132, 134. A plurality of pads 1522 are formed on the chip 152. The chip 152 is received in the space 150 and fixed on the base 146 by an adhesive glue 160. A plurality of bonding wires 156 are provided to connect the pads 1522 and the first conductive portion 132 of the conductors 130. The cover 158 is transparent and secured to the top of the sidewalls 1464 via an adhesive glue 162, thereby hermetically sealing the space 150 and allowing light beams to pass therethrough.
In the process of forming the conductors 130, a plurality of interconnection holes 166 are defined in the bottom board 1462. Then the third portions 136 are formed by plating so as to fill the interconnection holes 166. It is obvious that the method of forming the conductors 130 is complex and the cost is high. Furthermore, after the conductors 130 are formed, water vapor can enter the space 150 via the interconnection holes 166. Thus, the chip 152 will be polluted and the conductors 130 will be damaged.
In addition, the relative large volume of the image sensor chip package results in more dust-particles adhering to the cover 158, the bottom board 1462 and the sidewalls 1464 of the base 146. Thus, more dust-particles will drop onto the chip 152. The dust-particles obscure the optical path and produce errors in the image sensing process. Accordingly, the quality and/or reliability of the image sensor chip package can be effected.
Moreover, the bonding wires 156 exposed in the space 150 lack protection, thus are easy to be damaged by dust-particles in the space 150.
What is needed, therefore, is an image sensor chip package with reliability and high image quality.